dhcpd-pools/contrib/munin_plugins/dhcpstats_percent.js

#!/usr/bin/env node

var command = "dhcpd-pools"
var timeout = 5000;     // (ms) if the command take longer, then kill it

var execFile = require('child_process').execFile;
var echo     = require('util').print;

var arg = process.argv[2];

if ("autoconf" === arg) {
    echo("yes\n");
    return 0;
}

execFile(command, [ "--format=j", "--sort=n" ], { timeout: timeout }, function(error, stdout, stderr) {
    if (error !== null) {
        console.log('exec error: ' + error);
        return 1;
    }

    stdout = JSON.parse(stdout);

    if ("config" === arg) {
        echo("graph_title dhcp usage (in percent)\n");
        echo("graph_args --upper-limit 100 -l 0 --rigid\n");
        echo("graph_vlabel %\n");
        echo("graph_scale no\n");
        echo("graph_category network\n");

        stdout["subnets"].forEach(function(subnet) {
            var location = subnet["location"];
            var range    = subnet["range"];
            echo(location + '.label ' + location + ' (' + range + ')\n');
            echo(location + '.warning 75\n');
            echo(location + '.critical 90\n');
        });
    } else {
        stdout["shared-networks"].forEach(function(network) {
            var location = network["location"];
            var used     = network["used"];
            var defined  = network["defined"];
            // keep 1 digit after decimal point
            var percent  = Math.ceil(used * 100 / defined) / 10;
            echo(location + '.value ' + percent + '\n');
        });
    }

});